Most people are aware that there is a so-called “mystery illness” going around.

A “mystery illness” that is paralyzing some kids.

What’s so mysterious about it?

What is Acute Flaccid Myelitis?

Lots of things are mysterious about acute flaccid myelitis…

We don’t know exactly what causes it, who will get it, why they get it, or how to treat it, etc.

What do we know?

AFM is not new, although we are seeing more cases lately

AFM refers to acute (sudden onset) flaccid (droopy or loose muscles) myelitis (inflammation of the spinal cord) and it is a subtype of acute flaccid paralysis

most cases occur in children, with the ages of affected children ranging from 5 months to 20 years, although some adults have been affected

these children have a magnetic resonance image (MRI) showing a spinal cord lesion largely restricted to gray matter and spanning one or more vertebral segments

it is thought that AFM can be caused by viruses (polio, non-polio enteroviruses, West Nile virus, Japanese encephalitis virus, CMV, EBV, adenovirus, etc., environmental toxins, and genetic disorders, and although no common etiology has been found in these recent cases, most experts think that these cases are caused by a neuroinvasive infectious process, likely of viral etiology, including EV-D68 and EV-A71.

these cases of AFM are not thought to have a post-infectious immune-mediated etiology

cases are occurring sporadically – after 120 cases in 34 states in 2014, there were only 24 cases in 17 states in 2015, but then 149 cases in 39 states in 2016 and 33 cases in 16 states in 2017. And there have been at least 158 cases in 36 states in 2018, with another 153 cases under investigation.

outbreaks of EV-D68 and sporadic cases of AFM have also been seen in other countries recently, including Denmark, France, the Netherlands, Spain, Sweden and the United Kingdom (UK)

most cases occur in the late summer and early fall

most had symptoms of a preceding viral illness, including respiratory symptoms or diarrhea

While that’s a lot of good information, for parents wanting to protect their kids and avoid AFM, there is some key information missing. Same for those wanting to help treat their kids who have or have had AFM.

So although some folks don’t like that it is being called a “mystery illness,” there is still a lot of mystery to it.

You would first have to make a individual vaccines, before thinking about combining them, and you can’t just make any vaccine you want. If you could, we would have vaccines to protect us against RSV, malaria, HIV, and many other diseases.

Still, since EV-A71 also causes serious outbreaks of hand, foot, and mouth disease in some parts of the world, a vaccine has actually been in development for some time, and two are approved for use in China. That at least means making an EV-A71 vaccine is possible, although we would likely need to make our own.

Why did they make a vaccine for a virus that causes hand, foot, and mouth disease (HFMD)? Because unlike the HFMD that we are used to, which is typically caused by coxsackievirus A16 virus, another enterovirus, when caused by EV-A71, it can be deadly, as we have seen in outbreaks in Asia.

What about an EV-D68 vaccine?

While likely possible, since developing a new vaccine takes a lot of time, we want to be sure that is what is causing the outbreaks.

Do some kids not have either EV-D68 or EV-A71 because it just isn’t detected or because something else is causing them to have AFM? Possibly. One of the biggest issues that is troubling some experts though is that they have not detected these enteroviruses in the spinal cord fluid of many children, as you would expect if the viruses were causing the damage.

But even if these enteroviral infections are the cause, are there other risk factors that make some kids who get these enteroviral infections more predisposed to develop AFM, instead of more typical viral symptoms, like a cold or diarrhea?

And why are we seeing cases now? Did the virus, if that is the cause, just mutate into one that is more virulent?

Hopefully we get some more answers and a way to prevent, treat or cure AFM soon.

Until then, we can make sure we take steps to prevent the known causes of AFM, including polio (get vaccinated) and West Nile virus (use insect repellent), and wash hands properly to help avoid all other viral infections. You also want to get your flu vaccine! The flu can cause Guillain-Barré syndrome, which can also cause AFM.

“…is there any relationship between vaccination status and a developing acute flaccid myelitis? Meaning, are vaccines a risk factor? And the data so far says no, the overwhelming number of children who have gotten AFM have had no recent vaccination of any kind or vaccine exposure. These cases over these years have been happening before flu season and flu vaccination starts, which is one of the questions that comes up, and there hasn’t been any pattern to vaccine exposure of any kind in developing AFM. So far, we have not found a link between the two.”

What to Know About Acute Flaccid Myelitis

While it might be scary to think that there is a new condition out there that we don’t know everything about, parents should be reassured that experts are actively seeking the cause and a way to both prevent and treat AFM.